Flushable disposable absorbent products

ABSTRACT

A body fluid absorptive and retentive product, such as a sanitary napkin, having an absorbent core and a waterproof moisture barrier, is wrapped in a wrapper material comprising a cover and a water-soluble or water-dispersible material which (1) maintains the structural stability of the absorbent product during use, and (2) is capable of disintegration upon subsequent treatment with water, whereby it may be disposed of readily and safely, such as by flushing in an ordinary water closet or toilet bowl.

United States Patent Michael Loyer South Somerville, NJ. 807,780

Mar. 13, 1969 Apr. 20, 1971 Personal Products Company Inventor Appl. No.Filed Patented Assignee FLUSHABLE DISPOSABLE ABSORBENT PRODUCTS3,123,075 3/1964 Stamberger 128/287 3,406,688 10/1968 Cubitt l28/290X3,480,016 1 H1969 Constanza et al. 128/284 3,510,587 5/1970 Marder etal. 128/284 Primary Examiner--Charles F. Rosenbaum Attorneys-AlexanderT. Kardos, W. Frederick Mayer, Jr. and

Robert L. Minier ABSTRACT: A body fluid absorptive and retentiveproduct, such as a sanitary napkin, having an absorbent core and awaterproof moisture barrier, is wrapped in a wrapper material comprisinga cover and a water-soluble or water-dispersible material which (1)maintains the structural stability of the absorbent product during use,and (2) is capable of disintegration upon subsequent treatment withwater, whereby it may be disposed of readily and safely, such as byflushing in an ordinary water closet or toilet bowl.

lFlL USlllAlBlLlE lDlSSABLlE ABSORBENT PRODUCTS This invention relatesto disposable body fluid absorptive and retentive products and moreparticularly to sanitary napkins which are readily and safely disposedof by deposition in a body of water, such as by flushing in an ordinarywater closet or toilet bowl.

One of the more common problems which are involved in the use of bodyfluid absorptive and retentive products, such as sanitary napkins, isthe difficulty andinability to readily and safely dispose of suchproducts after use by flushing in an ordinary water closet or toiletbowl.

It is essential that such absorbent products maintain their structuralstability and shape when they are called upon during use to absorb andretain body fluids and exudates. Failure to do so wherein the absorbentproduct either comes apart or othenrvise fails during use leads to direpersonal consequences and very embarrassing situations. Structuralresistance to fluids during use is therefore a necessity for suchabsorbent products.

However, once the absorbent product has been used and has served itspurpose, it is extremely advantageous that it be water dissolvable ordispersable, or at least water disintegrable, whereby it can be readilyand safely disposed of, such as by deposition in a body of water byflushing in a standard water closet or toilet bowl.

The principal purpose of the present invention is therefore to provide adisposable absorbent product, such as a sanitary napkin, capable ofabsorbing and retaining body fluids and exudates during use withoutlosing its structural stability and shape but also capable of rapidlyand safely dissolving, dispersing, or disintegrating after use bydeposition in a body of water, such as by flushing in an ordinary watercloset or toilet bowl.

The present invention will be described with greater particularity byreference to a sanitary napkin as the disposable absorbent product butit is to be appreciated that the general principles of the presentinvention are equally applicable to other disposable absorbent productswherein similar use and disposability requirements are involved. Typicalof such other disposable absorbent products are surgical dressings,disposable diapers, compresses, hospital underpads, etc. For largerproducts such as hospital underpads, deposition in a tank containing alarger volume of water accompanied by agitation, if necessary, isdesired prior to flushing or other discharge into a sewer system.

The invention will be described and illustrated in greater particularityby reference to the following specification and accompanying drawingswherein:

FlG. l is a perspective drawing of a portion of a tabless sanitarynapkin, partially in cutaway view to disclose the interior componentsthereof;

FIG. 2 is a perspective drawing of a portion of a sanitary napkinsimilar to FIG. l but being provided with tabs at the ends thereof;

FIG. 3 is a cross-sectional view of the sanitary napkin of FlG. l, takenon the line 3-3 thereof, looking in the direction indicated;

FlG. ll is a schematic, cross-sectional view of the sanitary napkin ofFIG. 2, taken on the line 4-4 thereof, looking in the directionindicated; and

FlG. 5 is a cross-sectional view, similar to FIG. 3 but disclosinganother embodiment of the principles of the present invention.

Referring to FIG. 1, there is shown a sanitary napkin comprising anabsorbent core or pad 112, a waterproof moisture barrier M, and a covermaterial 116 which is wrapped around the absorbent core 112 and thewaterproof moisture barrier M to maintain such elements in properposition during use.

The absorbent core 112 normally comprises one or more bodies or layersof highly absorbent, relatively dense, fibrous materials customarily ofa cellulosic origin such as cotton, rayon, wood pulp fluff, etc. Thesebodies or layers are generally in the fon'n of carded cotton or rayonwebs, air-laid cellulosic fibrous webs, comminuted wood pulp bats,absorbent tissue, etc.

The waterproof moisture barrier 14 comprises a fluid repellent film orfilmlike material and is so shaped as to conform generally to the bottomand sides of the absorbent core 12 (see FIG. 3). As such, it possesses aconcave, boatlike construction having a U-shaped cross section. Theparticular configuration of the waterproof moisture barrier 14 is not ofthe essence of the invention. lt is merely required that the boatlikewaterproof moisture barrier 14 be capable of normally preventing fluidsdeposited on the absorbent core 12 from migrating or passing beyond theconfines thereof.

The waterproof moisture barrier 14 normally comprises a film made of awater-insoluble, synthetic organic material such as polyethylene,polypropylene, polyvinyl chloride, polytetrafluoroethylene,polytrifluoro chloroethylene, cellulose acetate, vinyl chloride-vinylacetate copolymer, etc. Films of such materials are availablecommercially in thicknesses ranging down to about 0.2 mil, Within thepreferred limits of the present invention, thicknesses of the waterproofmoisture barrier are in the range of from about 0.2 mil to about I mil.Heavier films may be used, if desired or required. Other waterproofmoisture barriers such as repellent paper tissue, wax or paraffin paper,etc., may be used.

The cover material 16 is made of a porous, water-pervious materialconventionally used as the wrapper or cover for sanitary napkins.Nonwoven fabrics of cotton or rayon fibers are preferred but wovenfabrics such as gauze; knitted fabrics such as tricot; etc., are also ofuse. The cover material to and the underlying absorbent core 12 areadapted to be placed in proximity to and to conform to the contours of abody during use and to receive and retain body fluids or exudatetherefrom.

The sanitary napkin may be tabless, as shown in FIG. 1, or, as shown inFIG. 2, it may possess a tab 18 at each end for attachment during use.

In the modification of FlGS. 1-4 and as most clearly shown in FIG. 3,the ends 20 and 22 of the cover 16 do not meet and a space or gap isthereby created which, of course, runs the full length of the bottom ofthe sanitary napkin It).

The width of the cover 16 should be sufficient as to cover the entiretop surface of the absorbent pad 12, go completely down the lateralsides thereof, and partially wrap around the bottom surface sufficientlyinwardly of the edges thereof that the sidewalls of the waterproofmoisture barriers 14 be covered. Inasmuch as the width of an averagesanitary napkin is about 2% inches and the lateral sides require atleast about /1 inch additional material, and since it is desired that atleast about another V; inch of the bottom surface be covered on eachside, such will result in the width of the cover being in the range offrom about 4 /2 inches to about 6 inches. A gap or space of from about Ainch to about A inches is thus created.

A water-sensitive or water-activatable strip of material 24 is adaptedto close this space or gap and hold the ends of the cover to in properposition during use. The strip is secured in place to the ends of thecover to by adhesive spots or lines 26 and 28.

The width of the water-activatable strip 24 is sufficient to completelycover the gap and to provide sufficient overlap with each end of thecover to enable suitable adhesion thereto. In practice, the width of thewater-activatable strip is in the range of from about 1 inch up to about2 inches.

The water-sensitive or water-activatable strip 24, is made ofwater-soluble or water-dispersible material and is capable of dissolvingor dispersing immediately upon being placed in a body of water such asis normally present in a standard water closet or toilet bowl.

The water-activatable strip 24 is normally a water-soluble orwaterdispersible paper or film, such as the known, commerciallyavailable water-soluble papers, or it could be a water-soluble syntheticorganic film of polyvinyl alcohol, a water-soluble ether of cellulosesuch as methyl cellulose, ethyl cellulose, etc., water-solublepolyethylene oxide, and the like.

Natural film-forming water-soluble organic materials such as gumtragacanth, alginates, etc., are also of use. Water-dispersiblematerials may also be used, such as fiber RD-lOO and/or fiber RD-lOl,water-dispersible, bonded combination fibers comprising short cellulosefibers and long, flat, hydrophilic, ribbonlike, aerated regeneratedcellulose fibers of the general collapsed, multicellular form. Suchfibers are described more specifically in U.S. Pat. 3,171,773 whichissued Mar. 2, 1965.

The water-activatable strip 24 should be as thin as convenientlypossible as long as it possesses sufficient strength to perform itsbasic purpose of keeping the ends of the cover 16 in position duringuse. The thickness of the wateractivatable strip 24 is normally in therange of from about 0.02 mil to about 0.2 mil but other thicknesses areof use, if desired or required.

Substantially any adhesive may be used to bond the sanitary napkin covermaterial 16 to the water-activatable strip material 24. However,water-based adhesives made from materials which can be dissolved ordispersed in water are preferred. Examples of such adhesives includestarch, dextrin, animal glue, blood albumin, egg albumin, methylcellulose, polyvinyl alcohol, etc.

It is to be appreciated that during use any body fluids or exudateswhich are deposited on the cover 16 will flow into the absorbent pad 12but will not normally be permitted to flow beyond the absorbent padbecause of the waterproof moisture barrier 14. In this way, thewater-activatable strip 24 remains unaffected and continues to hold theends of the cover 16 in proper position.

However, after use, the sanitary napkin 10 may be deposited in the waterpresent in a toilet bowl, whereupon the water-activatable strip 24immediately dissolves or disperses, the cover 16 immediately opens, andthe sanitary napkin 10 comes apart. The coming apart of the sanitarynapkin 10 is, of course, facilitated and expedited by the fact that theends 20 and 22 of the cover material 16 are in contact with the smooth,slippery film surface of the moisture barrier 14. There is very littletendency for such pans to cling together, either mechanically orphysically, and separation takes place immediately in a few seconds.Flushing of the sanitary napkin disposes of it readily and promptly.

A modification of the sanitary napkin 10 is illustrated in FIG. whereinthere is shown a sanitary napkin 110 having an absorbent core 112, aboatlike waterproof moisture barrier 114, and a cover material 116having ends 120 and 122 which are wrapped around the absorbent core 112and the waterproof moisture barrier 114 to maintain such elements inproper position during use.

The absorbent core 112, the waterproof moisture barrier 114 and thecover 116 are basically similar in construction, nature and function tothe absorbent core 12, the waterproof moisture barrier 14, and the cover16 respectively, of the sanitary napkin 10. However, the ends 120 and122 of the cover material 116 are secured in position bywateractivatable adhesive materials 126 and 128 directly to thewaterproof moisture barrier 114. These water-activatable adhesivematerials 126 and 128 are similar to the adhesive materials 26 and 28previously described herein.

If desired, the cover 116 may be made sufficiently wide that the endsthereof reach each other and overlap on the bottom of the sanitarynapkin 110. In such a construction, merely one line of water-activatableadhesive material will be required to secure the overlapped endstogether. Deposition in water will activate the adhesive and it willlose its grip on the ends of the cover material 116, thus permittingthem to open whereby the component parts of the sanitary napkin 1separate.

More specifically, the water-activatable adhesive I26 and 128 is readilywater-soluble or water-dispersible in a body of water as is present in astandard water closet or toilet bowl. It may be selected from the listof water-soluble or dispersible adhesives listed hereinbefore. However,inasmuch as rapid dissolution or dispersion is preferred, the morewater-sensitive adhesives should be selected or disposal problems mayarise.

It is to be appreciated that the adhesively bonded cover 116 will holdthe sanitary napkin together in proper fashion during use but, uponbeing placed in a body of water, will open to permit the components ofthe sanitary napkin to come apart and be readily and safely disposed ofin the water of a water closet or toilet bowl.

The invention will be described in greater particularity by reference tothe following examples wherein there is set forth specific embodimentsof the present invention for illustrative but not for limitativepurposes. The broader aspects of the invention, therefore, are not to beconstrued as limited thereby but possess a scope defined by the claimsappended hereto.

EXAMPLE I A sanitary napkin such as illustrated in FIG. 1 is made froman absorbent core of woodpulp fluff, a U-shaped, boatlike waterproofpolyethylene moisture barrier having a film thickness of about 0.5 mil,and a rayon nonwoven fabric cover adhesively held together by a strip ofwater-soluble polyvinyl alcohol film having a thickness of about 0.1mil. Upon being placed in a body of water in a standard toilet bowl, thewatersoluble polyvinyl alcohol film dissolves immediately, the woodpulpfluff pad falls apart in the water, and the entire sanitary napkinseparates into its various components, allowing it to be readily andsafely flushed. A specially manufactured toilet bowl having atransparent exit pipe with two traps reveals that the sanitary napkin isseparated into its separate components before it has travelled 5 feetalong the exit pipe or traps. No blocking or clogging of the exit pipe,traps, or of the sewer system is observed.

EXAMPLE II The procedures of Example I are followed substantially as setforth therein with the exception that DlSSOLVO cellulose polymer solublepaper (Gilbreth Co., Philadelphia, Pa.) is used as the water-activatablestrip. The results are similar and are equally satisfactory. TheDlSSOLVO" cellulose polymer soluble paper comes apart in the toilet bowlin a matter of a few seconds.

EXAMPLE 11] A sanitary napkin such as illustrated in FIG. 5 is made fromthe materials set forth in Example 1. The nonwoven fabric cover isadhesively bonded to the polyethylene moisture barrier by awater-soluble polyvinyl alcohol adhesive. Upon being placed in the waterin a toilet bowl, the sanitary napkin goes into pieces and is readilyand safely flushed without any blockage or clogging of pipes or traps,or of the sewer system.

Although the present invention has been described with reference to thepreceding examples wherein specific embodiments and materials wereshown, the invention is not to be limited thereto except as defined inthe following claims.

lclaim:

.1. An absorbent product for absorbing body fluids which comprises: anabsorbent core adapted to be placed in proximity with the body toreceive body fluids; a waterproof moisture barrier overlying the surfaceof said absorbent core worn away from the body and adapted to deter thespread of body fluids beyond said absorbent core; a cover materialwrapped around said absorbent core and said waterproof moisture barrierwith its edges overlying the outer surface of said moisture barrier andadapted to maintain said absorbent core and said moisture barrier inproper position during absorption of body fluids; and water-activatablemeans engaging the edges of said cover material and being capable ofholding said cover material in position to maintain the structuralstability of said absorbent product during absorption of body fluids butcapable of activation upon subsequent treatment with water to disengagethe edges of said cover material thereby permitting disintegration ofsaid absorbent product.

2. An absorbent product as defined in claim 1, wherein thewater-activatable means is a water-dispersible material.

3. An absorbent product as defined in claim 1, wherein thewater-activatable means is a water-soluble material.

4. An absorbent product as defined in claim 3, wherein the water-solublematerial is a water-soluble paper.

5. An absorbent product as defined in claim 3, wherein the water-solublematerial is water-soluble polyvinyl alcohol.

6. An absorbent product as defined in claim 3, wherein the covermaterial covers only a portion of the bottom of said absorbent core andsaid waterproof moisture barrier and the water-activatable means is astrip of water-soluble material which covers that portion of the bottomof said absorbent core and said waterproof moisture barrier which is notcovered by said cover material; and means to adhere said cover materialto said strip of water-soluble material.

7. An absorbent product as defined in claim 6, wherein the strip ofwater-soluble material is a water-soluble paper. 7

8. An absorbent product as defined in claim 6, wherein the strip ofwater-soluble material is water-soluble polyvinyl alcohol.

9. An absorbent product as defined in claim 3 wherein the cover materialcovers only a portion of the bottom of said absorbent core and saidwaterproof moisture barrier and the water-activatable means are lines ofwater-soluble adhesive which secure the spaced apart edges of said covermaterial directly to the waterproof moisture barrier.

10. An absorbent product as defined in claim 3 wherein the covermaterial surrounds said absorbent core and said waterproof moisturebarrier with its longitudinal edges overlapping on the outer surface ofsaid moisture barrier and the water-activatable means is a line ofwater-soluble adhesive adapted to secure the overlapped edges of saidcover material together.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION patent 3,515, 73Dated April 20, 1971 Inventor) Michael Loyer It is certified that errorappears in the above-identified patent and that: said Letters Patent arehereby corrected as shown below;

In Column 2, line 5 inches" should read "1% inches--.

Signed and sealed this 13th day of July 1971.

( SEAL) Attest: I

EDWARD M.FLETCHER,JR. WILLIAM E. SGHUYLER, J Attesting OfficerCommissioner of Patent

1. An absorbent product for absorbing body fluids which comprises: anabsorbent core adapted to be placed in proximity with the body toreceive body fluids; a waterproof moisture barrier overlying the surfaceof said absorbent core worn away from the body and adapted to deter thespread of body fluids beyond said absorbent core; a cover materialwrapped around said absorbent core and said waterproof moisture barrierwith its edges overlying the outer surface of said moisture barrier andadapted to maintain said absorbent core and said moisture barrier inproper position during absorption of body fluids; and wateractivatablemeans engaging the edges of said cover material and being capable ofholding said cover material in position to maintain the structuralstability of said absorbent product during absorption of body fluids butcapable of activation upon subsequent treatment with water to disengagethe edges of said cover material thereby permitting disintegration ofsaid absorbent product.
 2. An absorbent product as defined in claim 1,wherein the water-activatable means is a water-dispersible material. 3.An absorbent product as defined in claim 1, wherein thewater-activatable means is a water-soluble material.
 4. An absorbentproduct as defined in claim 3, wherein the water-soluble material is awater-soluble paper.
 5. An absorbent product as defined in claim 3,wherein the water-soluble material is water-soluble polyvinyl alcohol.6. An absorbent product as defined in claim 3, wherein the covermaterial covers only a portion of the bottom of said absorbent core andsaid waterproof moisture barrier and the water-activatable means is astrip of water-soluble material which covers that portion of the bottomof said absorbent core and said waterproof moisture barrier which is notcovered by said cover material; and means to adhere said cover materialto said strip of water-soluble material.
 7. An absorbent product asdefined in claim 6, wherein the strip of water-soluble material is awater-soluble paper.
 8. An absorbent product as defined in claim 6,wherein the strip of water-soluble material is water-soluble polyvinylalcohol.
 9. An absorbent product as defined in claim 3 wherein the covermaterial covers only a portion of the bottom of said absorbent core andsaid waterproof moisture barrier and the water-activatable means arelines of water-soluble adhesive which secure the spaced apart edges ofsaid cover material directly to the waterproof moisture barrier.
 10. Anabsorbent product as defined in claim 3 wherein the cover materialsurrounds said absorbent core and said waterproof moisture barrier withits longitudinal edges overlapping on the outer surface of said moisturebarrier and the water-activatable means is a line of water-solubleadhesive adapted to secure the overlapped edges of said cover materialtogether.